Metal tread



P. KASS.

METAL TREAD.

APPLICATION FILED JUNE 4.1917.

Patented June 10, 1919.

PETER KASS, OF CHICAGO, ILLINOIS.

METAL TREAD.

Specification of Letters Patent.

Qontinuation in part of application Serial No. 828,309, filed March 30, 1914. This application filed June 4,

1917. Serial No. 172,622. i

To all whom it may concern:

" Be it known that I, PETER KAss, a citize of the United States, and a resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Metal Treads, of which the following is a specification.

The present application is a continuation in part of an earlier application filed by me in the United States Patent Office on March 30, 1914, Serial No. 828,309, and which aplication resulted in United States Letters Batent 1,256,905, issued to me on February 19, 1918.

The present improvement relates to metal treads for steps, platforms and the like and particularly for use upon the steps and platforms of railway cars and stations. The invention seeks to provide a tread which can e inexpensively formed of sheet metal and which will provide an extremely durable safety tread surface.

The invention consists in the features of improvement hereinafter set forth, illustrated in the preferred forms in the accompanying drawing and more particularly pointed out in the appended claims.

In the drawing, Figure 1 is a vertical section of the improved metal tread in the form of a step for railway cars and the like. Fig. 2 is a partial plan view of the step shown in Fig. 1. Figs. 3 and 4 are enlarged detail sections illustrating different forms of the improved metal tread. Fig. 5 is an enlarged detail view illustrating the method of forming the raised bosses of the tread. Fig. 6 is a partial plan View illustrating a modification.

The improved tread is formed of a sheet or plate of wrought iron or steel and preferably of comparatively soft sheet steel. It may be applied tothe surface of steps and platforms now in use or, if desired, it may constitute the body of the .step structure. When forming the step structure, as shown in Figs. 1 and 2, the tread a is prefer ably provided with integral strengthening. flanges b and 0 at its front and rear-edges, the flange I) being preferably rounded to form a nosing at the front edge of the step. As shown, the step or tread is boltedat its ends to angle bars d which, in turn, are riveted or otherwise suitably secured to the usual side supports e. The greater portion of the surface of the tread or step is protral parts of the bosses Patented June 10, 1919.

vided with rows of staggered bosses f, the

front row being preferably located closely adjacent the rounded nosing c. The tread or step is extremely strong and rigid and need be supported only at its ends.

The bosses f are pressed up from the metal body of the plate and, in order to form a durable tread surface, sections of the plate are forced bodily upward in a direction at right angles thereto and in such a manner that the metal is drawn at the edges of the sections or bosses. Suitable male and female dies 1 and 2 for this purpose, are illustrated in Fig. 5. As shown, the bore of the female die is slightly larger than the working end portion of the male die, but the space between the working faces of the dies is less than the thickness of the plate. so that the metal is drawn out, as indicated, about the edges of the forced up sections or bosses, while the central portions of the bosses, vwhich form the tread surface, remain of substantially the same thickness as the body of the plate. Preferably, as indicated, the main body of each boss is forced up from the plate to a distance about equal to the thickness of the plate and the side walls of the bosses are convex or dome-shaped and are inclined or tapered toward the upper ends thereof at an angle of about 45 to the surface of the plate. The bosses f are prefera bly circular in horizontal section but may be square, as indicated at f in Fig. 6, or of other sectional outline.

The upper ends of the tapering bosses are, in effect, flattened 0r truncated and are provided With central cavities having continuous edges which are arranged in substantially the same horizontal plane and form the gripping tread surface. Such cavities may be formed either by providing the upper portions of the bosses with central perforations g, as indicated in Fig. 3, or with conical depressions or recesses g, as indicated in Fig. 4. The plate may be perforated either before or after the bosses are formed or at the same time by providing the male die Z with a central, projecting punch portion. The depressions g are formed by depressing or forcing down the upper cenwith a tool having a conical working end.

In either case, the continuous edges 9 of the cavities at the upper ends of the tapering bosses form a secure, anti-slipping tread or wear surface, such that, when the sole of the users shoe is pressed into contact wlth several of the bosses or knobs, the leather of the shoe sole will be pressed into the cavitles so the edges thereof will securely grip but will not damage the shoe sole. Preferably to avoid all danger of cutting the soles of shoes, any rough or sharp burs about the upper edges of the cavities are removed before the tread is put in use. The portions of the knobs or bosses which are sub ected to wear are of considerable thickness so that the improved construction forms a ,durable tread and one which will afford a secure foot hold. When used as a car step,

or when otherwise exposed to weather conditions, it is preferably provided with perforations, so exposed or when used as a cover for a solid step or platform, the construction shown in Fig. 4 is preferably employed.

It is obvious that changes may be made in the details set forth without departure from the essentials of the invention, as set forth in the claims.

I claim as my invention p 1. A metal tread comprising a plate having dome-shaped bosses struck up above the surface of the plate, the thickness of the central portions of the bosses above the plate being substantially the same as that of the plate itself, the upper surfaces of the bosses as indicated in Fig. 3. When not surfaces and the indentations and perfora-' tions, substantially as described.

2. A metal tread comprising a plate having sections thereof struck up bodily through a distance substantially equal to the thickness of the plate to draw the metal at the edges of said sections and form bosses'having convex side walls, said bosses being provided with central cavities having exposed surfaces which intersect the convex side walls of the bosses to form gripping edges all portions of which are arranged in substantially the same horizontal plane, substantially as described.

3. A metal tread comprising a late having sections thereof struck up t rough a distance substantially equal to the thickness inclined side walls, said bosses being centrally perforated and the perforations havof the plate to form truncated bosses having 7 ing exposed surfaces which intersect the inclined side walls of the bosses to form continuous edges of inverted V-shape about the upper ends of the perforations, said edges being arranged substantially in the same horizontal plane and forming a gripping tread surface the area whereof is restricted to said-edges, substantially as described.

. PETER KASS. 

